Mud and salt flats
Lake Bonneville deposits
Alluvium and colluvium
Oquirrh Group (10,000+ feet thick) of Cedar Mountains and vicinity, is equivalent, in part to Arcturus Formation and Ely Limestone elsewhere
Alluvial materials, Axtell and Harkers Formations
Prospect Mountain Quartzite (3,500 feet thick).
Oquirrh Group (maximum thickness 25,000 feet), including Bridal Veil Limestone.
Salt Lake Formation and other Basin & Range valley-filling alluvial, lacustrine, and volcanic materials. Valley fill is more than 8,000 feet thick in places and includes salt masses under the Sevier Desert.
Ochre Mountain Limestone (Great Blue equivalent) and Woodman Formation (Deseret Humbug equivalent).
McCoy Creek and Sheeprock Groups (10,000+ feet thick).
Isom Fm (tuff), Needles Range Fm (ash-flow tuff), Escalante Desert Fm (ash-flow tuff), Sawtooth Peak Fm (ash-flow tuff), and Tunnel Springs Tuff.
Trippe Ls, Marjum/Pierson Cove Fms, Wheeler Shale, Swasey Ls, Whirlwind Fm, Dome Ls, Chisholm Fm, Howell Fm, and Pioche Fm.
Ely Springs Dm, Eureka Qtz, Crystal Peak Dm, Watson Ranch Qzt, and the Pogonip Group (Lehman Formation, Kanosh Shale, Juab, Wah Wah, Fillmore, and House Limestones).
Pilot Shale, Guilmette Formation, and Simonson and Sevy Dolomites.
Great Blue Ls, Humbug Formation, and Deseret Limestone.
Notch Peak, Orr, Lamb, Weeks, and Wah Wah Summit Formations.
Gerster Limestone, Plympton Formation and Kaibab Limestone.
Granitic rocks (140 my) in House Range and near Wendover.
Older alluvial deposits
Intrusions, chiefly granitic, of various dates.
Diamond Creek Sandstone and Kirkman Limestone.
In Northwestern Utah: Dacitic tuff (8.5 my). In Logan-Huntsville Allochthon: rhyolite.
Granitic intrusions at Granite Peak.
Pinyon Peak Limestone and Victoria Formation.
Manning Canyon Shale.
Salt Lake Formation (?) and other Basin & Range valley-filling alluvial, lacustrine, and volcanic materials. Valley fill is more than 13,000 feet thick in the central part of Utah Valley.
Fish Haven Dolomite and Opohonga Limestone.
Gardison Limestone and Fitchville Formation.
In Western Utah: Quichapa Group and other volcanic rocks (Tmb,Tmr,Tma). In Central Utah: Silver Shield Latite (17 my) and Pinyon Creek Conglomerate.
Ely Limestone (chert).
Unit is present in all counties. Some counties divided the alluvium into younger and older units, and some did not. For those that did not, or used other generalized terms for Quaternary rocks, the unit Qal has been used for the general undivided alluvium. Additionally, when polygons have been edited and changed to alluvium, Qal was used as the general value; hence it now is present in all counties. Qya-Younger alluvium: Map unit is used in Churchill, Elko, Esmeralda, Eureka, Humboldt, Lander, and Lincoln Counties where geologic information suggests better-defined younger versus older alluvium. It is mostly interchangeable with Qal, except that it implies some specifically younger Quaternary deposits.
Silver City Monzonite (31 my), Sunrise Peak Monzonite Porphyry, Swanson Quartz Monzonite
Ajax Dolomite and Opex Formation (upper member of Maxfield Limestone).
Maxfield Limestone (Opex Fm, Cole Canyon Dm, Bluebird Dm, Herkimer Ls, Dagmar Dm, and Teutonic Ls) and Ophir Formation.
Present in Elko, White Pine, Lincoln, and Clark Counties. This unit represents mostly Upper Pennsylvanian and Lower Permian rocks that have not otherwise been separated into units Psc or IPMbc. Unit includes unnamed Pennsylvanian and Lower Permian limestone and sandstone beds in Lincoln County, the Bird Spring Formation in Clark County, the Riepe Spring and Ely Limestones (undivided) in White Pine County, and limestone and dolomite rocks not otherwise assigned in Elko County. This unit lies depositionally below unit Psc and above the Ely Limestone (IPMbc) where it is mapped separately. Where unit IPMbc is not mapped separately in southern Nevada, the unit lies directly on Mississippian carbonate (Mc) and in White Pine County it rests on undivided Chainman and Pilot Shales and Joana Limestone (shown as either unit IPMcl or MDcl).
Tuffaceous and other young Tertiary sedimentary rocks. Most of these rocks are sedimentary with a strong volcanic component - a few are tuffaceous with a strong sedimentary component. This unit includes rocks originally mapped as the High Rock sequence in Washoe County; the Horse Camp Formation in northern Nye County; the Esmeralda Formation in Mineral and Esmeralda Counties; older lake beds in Lincoln County; the Belted Range Tuff; the Indian Trail Formation (now abandoned); Timber Mountain, Paintbrush, and Crater Flat Tuffs; Wahmonie and Salyer Formations in southern Nye County; the Siebert Tuff in Esmeralda County; the Muddy Creek Formation in Clark County; and the Thousand Creek and Virgin Valley “beds” in Humboldt County; and other unnamed units. It corresponds to units Ts3 and Tts from the 1978 State map. It is present in all counties.
Map unit used in all counties for recent lake beds, playas, and flood plains. Polygons from the 1978 State map unit Qp were added where no playa was shown on the county maps.
Laguna Springs Latite, Tintic Mountain Group (latite, porphyry & tuff), Packard Quartz Latite, and Apex Conglomerate.
Rhyolitic flows, domes, plugs, breccias, quartz latite, rhyodacite, quartz porphyry dikes, and other shallow intrusive rocks. This unit includes rocks mapped as the Cañon Rhyolite on the Washoe North map, the Jarbidge Rhyolite and phenorhyolitic and phenodacitic flows and domes on the Elko County map, and other unnamed units. It has a distribution similar to Tt3, with exposures in the northern and southern parts of the State, but only crops out in a few places in the central region. It corresponds to unit Tr3 on the 1978 State map, and also includes a few rocks mapped as Trt on the 1978 State map. This unit is exposed in every county except White Pine.
Granodiorite, granite, and related rocks make up the largest group of granitic intrusions exposed in Nevada. They are present in every county, and are especially abundant in west-central Nevada in an arcuate belt along the border with California extending north and eastward towards Idaho.
This largely siliciclastic unit of siltstone, sandstone, limestone, and dolomite crops out in Elko, White Pine, Lincoln, and Clark Counties. It includes rocks originally mapped as the Arcturus Formation, Rib Hill Sandstone, undivided Kaibab Limestone, Toroweap Formation, and Coconino Sandstone in Clark County; and the Pequop Formation and red beds in Lincoln County. Unit Psc represents a strong influx of clastic material over the carbonate shelf during the Early Permian, presumably derived primarily from the craton to the east. It is depositionally overlain by unit Pc and lies conformably above unit PIPc. At its western and northern edges it can be difficult to distinguish from Permian clastic rocks of the Siliciclastic overlap assemblage (units Pacl and PIPacl). It follows closely with unit Psc of Stewart and Carlson (1978).
Unit includes andesite or dacite flows, flow breccias, and hypabyssal rocks in Lander County, andesitic to latitic flows, pyroclastic rocks, and phenoandesitic and phenolatitic flows in Elko County, and other undifferentiated volcanic rocks in other counties. Present in Humboldt, northern Nye, Churchill, Elko, Eureka, Lander, and White Pine Counties. It corresponds to the 1978 State map unit Ta1.